1. Field of the Disclosure
The present disclosure relates to a technique for detecting fluctuations in supply voltage.
2. Description of the Related Art
Known examples of techniques for detecting fluctuations in supply voltage include a technique for detecting fluctuations in supply voltage with respect to ground potential by comparing the supply voltage with a predetermined reference voltage (for example, Japanese Unexamined Patent Application Publication No. 11-211761, No. 2012-32254, No. 2004-348323, and No. 10-68747) and a technique for detecting fluctuations in supply voltage with respect to ground potential from changes in oscillation frequency of an oscillating circuit driven with the supply voltage (for example, Japanese Unexamined Patent Application Publication No. 2014-106112).
Since the above techniques are for detecting fluctuations in supply voltage with respect to ground potential, fluctuations in supply voltage concurrent with and similar to the ground potential cannot be detected.
For an apparatus that is significantly influenced by fluctuations in supply voltage concurrent with and similar to ground potential, it is preferable to also detect such fluctuations to reduce or eliminate malfunction of the apparatus.